As students head back to school this week, boys, as well as girls, will have funded access to the HPV vaccine Gardasil.

The rollout follows Pharmac’s decision last year to extend the vaccine programme. Though Gardasil is commonly known to protect against cervical cancer, human papillomavirus (HPV) also causes other cancers in both men and women.

The vaccine, which has been replaced with Gardasil9 that covers more types of HPV, is now offered to boys and girls through participating schools at Year 8.

The Science Media Centre asked experts to take part in a Q&A about the vaccine rollout. Feel free to use the comments below in your reporting.

Associate Professor Nikki Turner Director, Immunisation Advisory Centre; Associate Professor in the Division of General Practice and Primary Health Care, University of Auckland

Gardasil is mostly known for protecting against HPV-related cervical cancers, can you explain why it’s being extended to boys?

“The HPV vaccines were originally designed for protection against cervical cancer. However, it is now very clear that HPV viruses are causative agents for many more cancers than just cervical cancer. USA data shows they are implicated in around 90 per cent of cancer of the anus and approximately two-thirds of cancer of the penis and oropharynx (mouth/throat).

“While these cancers numerically are not as common as cervical cancer they still have significant impact, and in particular the rates of oropharyngeal cancer have been on the rise. Furthermore, the HPV vaccines Gardasil and Gardasil9 also offer protection against genital warts, the most common STI in NZ. It is expected that the vaccine should be more than 90 per cent protective against genital warts. Both Australian and NZ data to date have shown dramatic reduction in genital warts both for those vaccinated and the sexual contacts of the vaccinated (herd effects).

“The final argument for vaccinating young men is herd immunity protection to the wider community. While vaccinating young women offers herd immunity to their sexual contacts, vaccinating men as well offers broader herd immunity for the community, and particularly to groups who do not get protection from just women vaccination i.e. men who have sex with men. Hence there is a real ethical argument for offering the vaccination to men and women.”

What effect on HPV-related cancers can we expect from rolling the vaccine out to boys as well as girls? Is there evidence from overseas to support this?

“Most countries who have to date introduced HPV vaccine have focused on the cervical cancer strategy as this is the biggest killer and when resources are constrained – i.e. particularly in low- and middle-income countries – the cost-benefit lines up the strongest to offer the vaccine to young women.

“However, in countries with more resources the cost-benefit analysis when reductions in other cancers as well as genital warts are considered it becomes sensible to offer the vaccination to young men as well. To date, only a few countries have introduced to men and women, including Australia since 2013, and the US since 2009. It is likely that many more Western countries will be introducing an HPV programme for boys as well as girls over the next few years.

“Data to date shows dramatic declines in genital warts in vaccinated populations, boys and girls – however, we will need quite a few more years delivering to boys before we see the effect on cancer rates.”

What is the evidence for the safety of the Gardasil vaccine?

“The safety profile of Gardasil (with the 4 types) has been well documented, both in the original pivotal clinical trials but now also with extensive international experience. This vaccine has an excellent safety profile which has been reviewed and supported by the World Health Organization. The most common concern that arises is syncopal attacks (i.e. fainting), an effect of having an injection, which can be more common with teenagers. Anaphylaxis (i.e. very severe allergic reaction) is extremely rare but possible. All people vaccinated with any vaccine in NZ are asked to wait at the site of vaccination for 20 minutes after a vaccination to make sure there is no sign of anaphylaxis and all vaccinators in NZ are trained to treat if it does occur.

“When you are vaccinating a large number of people there will be events that occur after vaccination and with safety surveillance it is really important to identify all events and then focus the research on whether this is caused by the vaccine or coincidental. Careful analysis to date comparing vaccinated with non-vaccinated has not shown the vaccine to be associated with any other serious adverse events. Despite this, there is lots of noise in the social media about possible purported associations with a wide range of conditions. It is very important when looking at the social media concerns to be aware of the difference between careful research that checks out the difference between cause and coincidence, and a range of issues that arise when a person develops a medical condition that is unexplained or scary and they are wanting an explanation.

“The Gardasil9 vaccine that has been introduced to NZ this year is made in the same way as the Gardasil4 but it has extra protection for a further 5 types of HPV. The clinical trials have shown it to be slightly more likely to be associated with side effects such as soreness and redness at the injection site, fever and headaches but, otherwise, is acting in the same way as the Gardasil4 vaccine.”

What do parents need to know about having their sons (and daughters) vaccinated?

“Parents need to be aware that the vaccine is expected to be highly effective against a range of very nasty cancers, and against genital warts, and it has a well-established international safety record. Beware for those young people that may faint with needles.

“Younger people have a stronger immune response to the vaccine than as we get older so the recommendation is that for young people under 15 years of age they only need two doses, whereas if someone misses out on getting the vaccine when they are younger they need 3 doses to be as effective. This is a good reason not to delay vaccinating younger teenagers.”

Dr Swee Tan Executive director, Gillies McIndoe Research Institute

Gardasil is mostly known for protecting against HPV-related cervical cancers, can you explain why it’s being extended to boys?

“Worldwide there has been a rapid increase in the incidence of HPV-related throat cancer, especially in younger men. 70 per cent of throat cancers are caused by HPV infection, and most cervical cancers and penile cancers are caused by HPV infection.

“In New Zealand, there was a four-fold greater burden of throat cancer in men and tripling of the proportion of HPV-related throat cancer between 1994 and 2014. Extending vaccination to boys will reduce the incidence of HPV-related throat cancer and other HPV-related cancers, in both men and women.”

What effect on HPV-related cancers can we expect from rolling the vaccine out to boys as well as girls?

“HPV vaccination of boys and girls will reduce the carriage of HPV by reducing HPV infections in both males and females and thus preventing HPV-related throat cancer and other HPV-related cancers for both sexes.”

Is there evidence from overseas to support this?

“An overseas study has shown that HPV vaccination of girls and boys lead to reduction of viral carriage which will prevent throat cancer and other cancers caused by HPV infection.”

“Throat cancer and its treatment have devastating impacts on the quality of life and daily functioning of the affected individuals. Current treatment of oropharyngeal cancer is resource intensive. PHARMAC’s decision to extend HPV vaccination to boys is a cost-effective way to prevent HPV-related throat cancer and other HPV-related cancers.”

Gardasil is mostly known for protecting against HPV-related cervical cancers, why is it important to extend coverage to boys?

“Boys, as well as girls, can develop a range of nasty cancers related to HPV infection, especially oral cancers. Oral cancer rates are rising among men, and Gardasil will help protect boys against these occurring.”

What effect on HPV-related cancers can we expect from rolling the vaccine out to boys as well as girls? Is there evidence from overseas to support this?

“HPV vaccination programmes are now a major public health initiative globally with demonstrated impact in reducing disease. Vaccinating boys and girls will accelerate the health benefits enjoyed by New Zealanders. Already in Australia, their gender neutral vaccine programme has almost eliminated the early signs of HPV-related disease in young people such as genital warts. As those vaccinated young people age, we can expect to see a decline in HPV-related diseases that take longer to develop such as cancers of the cervix, mouth, penis and anus.“

What should parents consider when deciding to have their sons vaccinated?

“HPV is very easily transmitted and almost impossible to avoid unless you’re sexually abstinent for life. Vaccinating early is best because you never know when a teenager’s first time will be or who it will be with. Vaccinating boys also sends a positive message that protection against HPV-related disease is a shared responsibility. Shared responsibility and mutual care are good values to communicate to young people about their sexual health and their wellbeing generally.”

Gardasil is mostly known for protecting against HPV-related cervical cancers, can you explain why it’s being extended to boys?

“Equity. The vaccine is being extended to boys because the HPV virus causes cancers that affect them too, such as cancers of the throat, anus and penis. Boys also get genital warts, just like girls. Offering this vaccine to all our population makes it much fairer.”

What effect on HPV-related cancers can we expect from rolling the vaccine out to boys as well as girls? Is there evidence from overseas to support this?

“Less cancer. The vaccine has been demonstrated in clinical trials conducted across many countries, including New Zealand, to be effective in preventing several cancer types both male and female. It is estimated that it will prevent most of these anal cancers as well as about a third of cancers of the base of the tongue and oropharynx and nearly half of penile cancers. Early data from several countries is already showing a reduction in cervical cancer.

“By vaccinating boys we increase our overall immunity in the community. The more members of our community that are protected against infection the more effective our vaccine programmes are at preventing disease.”

What is the evidence for the safety of the Gardasil vaccine? What do parents need to know about having their sons (and daughters) vaccinated?

“There is an enormous body of evidence on the safety of HPV vaccines. Studies have been conducted all over the world using a range of approaches that compare outcomes in vaccinated and unvaccinated people. Some of these studies have over one million people in them. In fact, one study from Denmark and Sweden included almost two million. Of the seventeen large observational studies conducted and published since the vaccine has been available NONE have found any safety concerns what so ever. This is an extremely safe vaccine and parents need to know that.”

Why are children being offered this vaccine before they become sexually active?

“Three reasons. One, they make a superior immune response to the vaccine which means we can use a two-dose schedule, much easier to deliver! Two, the key to the vaccine’s success is administrating it PRIOR to sexual debut. As much as parents don’t like to think about it the fact is that around 20 per cent of our children have had sex by age 13. Three, delivering the vaccine programme to a large population has practical issues to consider. We already have systems to deliver the tetanus and pertussis vaccine booster in schools to using our school-based programme is very practical and convenient.”

Why should boys be vaccinated?

“So they don’t get warts on their willy.

“Let’s not lose sight of genital warts. Ugly, embarrassing and difficult to treat. Thousands of cases are reported in NZ every year. HPV vaccine has almost eradicated genital warts in Australia. In NZ the cases have halved since the vaccine was introduced. With higher coverage, we could get rid of them too.”

“HPV vaccine is very safe and effective at reducing the incidence of genital warts and HPV-related cancers.”

Conflict of interest statements

A.Prof Turner sits on the immunisation subcommittee that advised Pharmac on these changes. She is a member of the WHO Immunisation committee, SAGE, that gives international advice on vaccines, immunisation policy and strategy and is the chair of the measles and rubella subcommittee.

Dr Petousis-Harris is involved with studies that have been funded by GlaxoSmithKlein (GSK) and Novartis. She has served on expert advisory groups for GSK, Merck and Pfizer but did not receive an honorarium.

Dr Saxton and Dr Petousis-Harris are involved in studies of HPV prevalence and vaccine awareness, funded by the Ministry of Health and the Health Research Council of New Zealand.

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